Space closure is important in these cases. Good anchorage control is needed at the space closure stage in order to achieve incisor retraction into the available extraction space. First premolars are normally chosen for extraction. Second molars are included in the set-up if possible. In this way, six anterior teeth are balanced against six larger posterior teeth, giving a theoretical advantage in anchorage balance (Fig. 9.29). Palatal bars and lingual arches may be used during the alignment stage, to restrict mesial movement of molars, and the palatal bar may be continued into the space closure stage. If patient cooperation is available, a headgear may also be considered, sometimes with Class III elastics (Fig. 9.30).
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